In motor vehicle applications, particularly off the road vehicles, a fan situated behind a radiator draws a large quantity of air through the radiator, as the vehicle speed is relatively low. Low noise level is also a requirement. Therefore quieter compact fans are needed to reduce cooling system size and still meet the sound and cooling requirements of off road motor vehicles.
U.S. Pat. No. 4,358,245 describes a low noise, axial flow fan particularly suited for use in a turbulent airflow such as the flow existing in an automobile radiator. The fan has a shroud secured to the outer end of the fan blades. The blades are forwardly skewed and have an increasing blade angle as the blade extends outwardly. The shroud forms a converging nozzle. Each blade has an airfoil cross-section and the entire fan is formed as a single injection molded plastic integral structure.